Collapsible tap



Aug. 21, 1951 D. E. YOUTZ 2,564,827

COLLAPSIBLE TAP Filed Nov. 6, 1947 2 Sheets-Sheet 1 A v 1- w k INVENTOR.

) DONALD E. rourz Fla 2 as /0 BY ATTORNEY Aug. 21, 1951 D. E. YouTz 2,564,327

' COLLAPSIBLE TAP Filed Nov. 6, 1947 2 Sheet s-Sheet 2 Q e U mum WI/JIHEfilZ INVENTOR.

' DONALD E. YOUTZ ,7 FIG, 4. BY

Patented Aug. 21, 1951 UNITED STATES PATENT OFFICE COLLAPSIBLE TAP Donald E. Youtz, Irondequoit, N. Y., assignor to Consolidated Machine Tool Corporation, Roch.- ester, N. Y a corporation of Delaware Application November 6, 1947, Serial No. 784,428

Claims. (01. .10l45) The present invention relates to collapsi le taps.

In collapsible taps of known prior construction, the chasers cannot be adjusted radially without affecting the axial position of the chasers, that is,, the length of thread to be cut. Accordingly, with such taps, when a hang adial p s tion of the Chasers is made as, for instance, to suit the diameter of thread to be cut or to compensate for change in height of the chaser teeth due to sharpening, a compensating thread-length adjustment has also to be made. Moreover, with previous designs of collapsible taps, outside tools are required to client radial adjustment of the chasers.

ne object of the present invention is t pIO! vid an improved form of collapsible tap in which the adjustment for thread length remains une disturbed by radial adjustment of the chasers.

Another object of the invention is to provide a collapsible tap in which radial adjustment of the chasers can be efiected simply by an adjustment incorporated in the tap itself and without requiring any outside tools.

Another object of. the invention is to pr v d a collapsible tap in which the radial adjustment of the chasers is maintained without clamping or locking the Ch s rs th mselves.

A further object of the invention is to provide a collapsible tap having manually operable means forming part of the tap itself, for adjusteing the chasers radially in predetermined increments and having means for automatically releasably latching the adjusting means and Chasers in any adjusted position.

Another object of the invention is to provide a collapsible tap having means for automatically insuring radial adjustment of the chasers in predetermined increments and for visually indicating the amount of the adjustment as a check.

A further object of the invention is to provide a collapsible tap with an improved latching mechanism for holding the chasers in operative position which may quickly and easily be tripped to permit the chasers to be moved instantaneously away from operating position when the desired length of thread has been out.

Another object of the invention is to provide a collapsible tap having a mounting shank which is interchangeable to permit mounting the tap in difierent tool spindles.

A still further object of the invention is to provide a collapsible tap with a built-in axial float so that the thread being cut will itself control the accuracy of the cutting operation. there-. by to produce a high precision th ead...

2 I Still another object of the invention is to pro,- vide a collapsible tap which is more compact and has less overhang from the tool spindle than conventional designs.

Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims.

In the drawings:

Fig. 1 is a side elevation of a collapsible tap made accord n to emb d ment f the lo es tion;

Fi 2 is a central lo gi ud nal se tion th ou h this tap showing the chasers and other parts in operating positions;

Fi 3 is a ce tral longitud nal sect n hro gh h s tap taken approxi ate y at ri ht angle to the s c n o ig- 2 an showin th pos ions of the parts when ohase s ar e acted a d the tap s n o lapsed nd tio Fi 4 i a fro end iew with he ap r moved showin he co n n o the oh ser wit he core sin of e tap;

Fig. 5 is a transverse sectional View, taken approximately on the line 5-5 of Fig. 1 looking in the direction of the arrows, and showing details of the means for adjusting the chasers radially;

Fig. 6 is a transverse sectional view through the tap showing in released position the latching means which operates normally to hold the chasers in operating position; and

Fig. 7 is a fragmentary longitudinal sectional view showing more or less fragmentarily and as contrasted with Fig. 2 the positions of the parts an instant after the latching means has been tripped.

The tap illustrated in the drawings comprises a closing ring II] which is slidable upon a sleeve H and an adjusting ring l2. Glosing ring In is coaxial with adjusting ring 12 and sleeve H; The adjusting ring I2 is internally threaded at its inner end to engage the externally threaded rear end of the sleeve I] which is of reduced diameter. Thus by rotating ring 12 it can be adjusted axially relative to sleeve 1] and ring I0.

The sleeve 1 l and adjusting ring l2 are slid.- ably mounted upon a cylindrical body member M. This body member M has a central bore within which is mounted for axial sliding move? ment a core pin 15, The core pin has a tapered head 16 at its front end which .1 formed with a plurality of longitudinally inclined forwardly convers tongues l i These tongues re adapt d to a e in co plementary groov s I18 of the chasers 20. The ehasers are movable radia y n s ots onned in he body member:

They seat at their rear ends against the front face of the body member I4 and are held against axial movement relative to the body member by a cap 22. This is secured to the body member I4 by screws (not shown) that thread into holes 24 (Fig. 4) in the front face of the body member.

Because of the longitudinal inclination of the grooves I8 and tongues I! to the axis of core pin I5, the chasers are moved radially outwardly to engage the work, when the core pin is moved forward to the position shown in Fig. 2, and the chasers are moved radially inwardly to disengage the work when the core pin is moved rearwardly to the position shown in Fig. 3.

The core pin has a head 25 threaded into its rear end which is of larger diameter than the core pin. This head is adapted to slide in the bore of the body member I4 to guide the core pin in its axial movement. The core pin is connected to the adjusting ring I2 by a transverse pin 26 which is mounted in a hole in the head 25. The transverse pin projects at both sides from head 25 through a transverse slot 29 in body member I4 and seats against a shoulder '21 (Fig. 3) formed internally in the adjusting ring I2.

The core pin I is constantly urged rearwardly in the body member I4 by a coil spring 30. This spring seats at its rear end against the head member 25 and at its forward end against tongues (not shown) formed in the bore of body member I4. During a threading operation, the body member I4, the sleeve II and core pin I5 are held in the position shown in Fig. 2 so that the chasers 20 are in cutting position. For this purpose, the body member I4 and sleeve II are releasably latched to the closing ring I0 by a ball detent 33 (Figs. 2, 6 and 7). This ball is adapted to engage in a kerf 34 formed on the inside surface of closing ring III. The ball is held resiliently in engaging position by a crescent-shaped feather 35. This is housed in a slot in the body member I4 and is constantly urged outwardly by a coil spring 36 which is seated in a recess in the feather and engages at one end in the bottom of that recess and at its opposite end against the body member I 4. Dowel pins 31 insure against cocking of the feather. These are secured in the body member I4 and engage in holes 38 in the feather.

The latching mechanism is adapted to be tripped by rearward movement of closing ring III. This movement may be effected in conventional manner, for instance, by rearward movement of a trip plate 40, that is adapted to engage the work as the rotating tap is fed axially of the work. The trip plate is secured by screws M to arms 42 which are adjustably connected by screws 43 with the closing ring II). The arms 42 seat in longitudinal slots 45 formed on the periphery of the closing ring I0; and the screws 43 pass throughelongated slots 46 formed in the arms 43, and thread into the closing ring. The heads of the screws 43 clamp the arms 42 in the slots 45 of ring I0 in any adjusted position.

As the trip plate 40 is moved rearwardly by contact with the Work from the position shown in Fig. 2 to that of Fig. 3, the closing ring I0 is moved rearwardly, sliding on the sleeve II and adjusting ring I2. As the closing ring I0 moves rearwardly, the ball 33 is forced out of the recess 34 in the closing ring I0 against the resistance of coil spring 36, and the ball rides on the inside of ring II), as shown in Fig. 7. T1115.

forces feather 35 inwardly and disengages it from the circular groove 39 (Fig. 3) in sleeve II. This releases the sleeve II from its connection with the closing ring II). The coil spring 30, which surrounds the core pin I5, then becomes operative to force the core pin rearwardly and through the pin 26 to move the adjusting ring I2 and sleeve I I rearwardly, also. As the core pin moves rearwardly from the position shown in Fig. 2 to that of Fig. 3, the chasers 20 are moved radially inwardly by the core pin, and retracted from engagement with the work. Then the tap can be withdrawn axially without unthreading it from the work. Fig. 7 illustrates more or less diagrammatically an instantaneous position of the parts after tripping, for the spring 30 serves to move sleeve II rearwardly on body member I4 the instant the ball 33 is tripped out of recess 34; and this rearward. movement of sleeve II serves to hold feather 35 and spring 36 compressed until the sleeve and closing ring I0 are returned to their forward positions again.

From the preceding description, it will be seen that the feather is in the body member itself and that the whole latching device is well forward of the tap. In prior known constructions, the latch is in an intermediate member and is at the rear of the tap. Applicants structure is much more compact, simpler, and more rigid.

Another feature of the invention is the adjustment for diameter of the thread to be cut. This adjustment is effected by rotation of the adjusting ring I2. As this ring is rotated, the pin 26, which is held against the shoulder 21 of the ring by the coil spring 30, is moved forward or back, depending upon the direction of rotation of ring I2, to move the core pin I5 forward or back in the body member I4. Thus, the chasers 20 can be adjusted radially outwardly or inwardly for different diameters of thread and to compensate for the reduced height of the chaser teeth after sharpening, without adjusting them axially, that is, without in any wise disturbing the adjustment for thread length. This is an outstanding advantage of the present construction.

The adjustment of the ring I2 cari be made accurately. It is provided on its periphery with gradu-ations 50 (Fig. 1) which read against azero mark 5I (Fig. 5) that is provided in a recess 52 formed in the back face of the closing ring I0 The ring I2 is'knurled as denoted at 54 (Fig. 1) for manually gripping and rotating the ring. The ring may also be provided with holes 55 to receive a wrench for adjusting purposes. Internally, the ring is provided with a plurality of spaced notches 51 (Fig. 5). Preferably, there are an uneven number of these notches. Mounted in diametrically opposite holes 58 (Fig. 2) in the body member I4 are two ball detents 60 which are spring pressed outwardly by coil spring 6 I.

Because of the uneven number of notches 51, only one of the balls 60 can engage a notch 51 at a time. When one of the balls is engaged in a notch 51, the diametrically opposite'ball 66 will be riding on the land of the ring I2 between two notches 51. The number of notches 51 provided in ring I2 in practice is such that the landson ring I2 are no wider than the diameter of balls 60. This insures that the ring I2 is locked securely in each adjusted position and automatically by one of the balls. It also means that a very slight step-by-step radial adjustment of chase s c n be mad and. th chasers-W111 automatically be secured in any adjusted position. In practice, the grooves 251 may be spaced from one another a distance which represents .001 in adjustment in diameter of the chasers. By rotating adjusting ring l2, then, and listening to the balls Bil ratchet over the grooves -5l,"the operator can, from the number of clicks, determine the number of thousandths of an inch of diametral adjustment of the chasers which he makes. Hence, he has, in addition to the visual indication through the graduations 5i! and zero marking 51, an audible indication of the adjustment made.

As will be obvious, the adjustment of the chasers for diameter requires no outside tools. Moreover, when the .core pin 55 is adjusted, the positions of the spring 35, feather 3 5 and detent 33 remain unchanged, for the core pin moves longitudinally and am'ally .in the body member without moving the body member itself.

The tap is adapted to be mounted in the spindle of the machine on which it is to be used, by means of a shank ill. This shank may be made of any suitable shape to fit the bore of the spindle of the machine. It is disconnectable from the body, of the tap for substitution of a shank of any other shape. In addition, the shank has a floating connection with the body member 14 which is one of the features of the present invention.

The shank has a forwardly projecting portion H (Fig. 2) which engages in a oounterbored recess 12 of body member M. The shank is connected to the body member 14 by two diametrically opposed pins 14 (Fig. 3) which thread into the body member l4 and engage in diametrically opposed recesses 15 formed in the projection H of the shank. The recesses 75 are slightly larger in diameter than the diameters of the pins 14. Coil springs :18 (Fig. 2) that seat in holes IT in the rear face of the body member l4 press against the front face of the shank 10 to urge body member l4 resiliently forward with reference to the shank.

Chasers are ordinarily made with their front cutting teeth of slightly less height than the depth of the thread which is to be cut so that there will be gradual engagement of the chasers with the thread as the chasers are moved axially of the work. With the described connection between the shank Hl and the body member [4, there is an axial float possible between the. body member and the shank so that the thread which is being out into the work can control the axial position of the chasers during cutting and insure greater accuracy in the thread produced.

For the purpose of manually moving the closing ring I0 rearwardly to effect manual tripping of the tap or for moving the ring In forwardly to bring the notch 34 in the ring and the groove 39 in sleeve H into registry with ball 33 and feather 35 and allow the chasers to be latched in their projected or operative position again, a conventional handle 86 is provided. This handle is pivotally mounted in the ring I0 upon a transverse pin 8|. The pin extends diametrically through a spherically shaped boss 82 on the handle. The said boss fits within a suitably contoured slot 83 in the ring l0 so as to prevent l chips and dirt from getting into the interior of the tap. The inner end of the handle 88 projects through a slot 84 in the sleeve II and is provided with a spherical end 85 which engages a socket 86 formed in the body member I4.

The annular groove 90 in the closing ring In is provided so that the closing ring I!) may be moved forwardly or rearwardly, also, auto- 6 maticarliy by operation of the machine on which the tap 'is used. The groove 91] is adapted to receive a yoke operated "from the machine. The tripping plate 40 may "then be dispensed with or adjusted out of operatingposition.

While the inventionhas been "illustrated in connection with a particular embodiment thereof, it will be understood that it is capable of further modification; and this application is intended to cover any variations, uses, or adaptations, 'Of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the inxzention .relates and as maybe applied to the essential features hereinbe'fore set forth and as fall within the scope of the invention or the limits of the appended claims.

Having thus described my invention, what I claim is:

l. A collapsible tap comprising a body member, a plurality of radially movable thread-cutting chasers carried by said body member, a core-pin mounted in said body member for axial movement therein and connected to the chasers so that the chasers are movable radially on axial movement of the core-pin, :a sleeve mounted on .the body member for axial movement relative to the body member, a rotatably adjustable adjusting ring threaded on said sleeve and operatively connected to the core-pin to adjust the core-pin axially in the body member, a closing ring mounted on the sleeve for axial movement relative thereto,a spring-pressed detent mounted in the body member and adapted to engage the sleeve to latch the body member releasably to the sleeve with the core-pin in forward position and the chasers in operative position, means on the closing-ring operatively connected to the detent and adapted to release said detent on rearward movement of the closing ring, and means operative on release of the detent to move the core-pin rearwardly to retract the chasers.

2. A collapsible tap comprising a body member, a plurality of radially movable thread-cutting chasers carried by said body member, a core-pin mounted in said body member for axial movement therein and connected to the chasers so that the chasers are movable radially on axial movement of the core-pin, a sleeve mounted on the body member for axial movement relative to the body member, a rotatably adjustable adjusting ring threaded on said sleeve and operatively connected to the core-pin to adjust the core-pin axially in the body member, a closing ring mounted on the sleeve for axial movement relative thereto, a spring-pressed detent mounted in the body member and adapted to engage the sleeve to latch the body member to the sleeve with the core-pin in forward position and the chasers in operative position, means on the closing-ring operatively connected to the detent to release said detent on rearward movement of the closing ring, and means for locking the adjusting ring to the body member in any adjusted position comprising a pair of diametrically opposite spring-pressed detents mounted in one of said two parts to cooperate with grooves in the other of said two parts, said grooves being odd in number and equispaced whereby one or other of the detents locks the adjusting ring and sleeve together by engagement in one of grooves.

3. A collapsible tap comprising a body member, a plurality of radially movable thread-cutting chasers carried by said body member, a core-pin mounted in said body member for axial movement therein and connected to the chasers so that the chasers are movable radially on axial movement of the core-pin, a sleeve mounted on said body member to be movable axially relative thereto, and adjusting ring secured to said sleeve and threadably adjustable axially thereon, a pin connecting the core-pin with the adjusting ring so that the two are movable axially together, said pin being movable in an elongated axial slot in the body member, a closing-ring mounted to slide axially on both the sleeve and the adjusting ring, a ball detent mounted in the sleeve and adapted to engage a notch in the closing-ring, a feather mounted in the body member, a spring for urging said feather outwardly of the body member to hold the ball in engagement with the notch in the closing-ring to lock body member, sleeve, and closing-ring releasably together, and a coil spring surrounding the core-pin and interposed between the core-pin and the body member to hold the connecting pin against the adjustin ring and to urge the core-pin constantly rearwardly in the body member, said adjusting ring being manually rotatable to adjust the radial position of the chasers.

4. A collapsible tap comprising a body member, a plurality of radially movable thread-cutting chasers carried thereby, a core-pin mounted in said body member to reciprocate axially therein, a coil spring mounted within the body member about the core-pin and constantly urging the core-pin rearwardly in the body member to retract the chasers radially, a sleeve slidable axially on the body member, a pin secured to the corepin and passing through an axial slot in the body member and connecting the core-pin to the sleeve, a radially movable spring-pressed detent releasably connecting the body member to the sleeve to prevent rearward movement of the sleeve on the body member, and means for releasing said detent comprising a closing-ring slidable axially in the sleeve, and a ball mounted in the sleeve to engage the detent and closing-ring at diametrically opposite points, said closing-ring having a shallow recess in which the ball seats when the chasers are in cutting position but out of which the ball rides on rearward movement of the closing-ring.

5. A collapsible tap comprising a body member, a plurality of radially movable thread-cutting chasers carried thereby, a core-pin mounted in said body member to reciprocate axially therein and connected to the chasers so that the chasers are movable radially in opposite directions on movement of the core-pin axially in opposite directions, a sleeve slidable axially on the body member, an adjusting ring secured to the sleeve and axially adjustable thereon, means connecting the core-pin to the adjusting ring, a spring mounted in the body member about the core-pin and continuously urging the core-pin, adjusting ring and sleeve rearwardly to retract the chasers radially, a detent releasably connecting the body member and sleeve to prevent rearward movement of the sleeve on the body member, and means for releasing said detent comprising a closing-ring axially slidable on the sleeve, and a movable member carried in the sleeve and interposed between the closing-ring and the detent to move the detent to released position on rearward axial movement of the closing-ring.

DONALD E. YOUTZ.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,083,040 Wells Dec. 30, 1913 1,376,791 Baker May 3, 1921 1,772,018 Shrum Aug. 5, 1930 1,813,480 Brown July 7, 1931 2,135,067 Breitenstein Nov. 1, 1938 2,381,448 Hogg Aug. 7, 1945 

